We could try teaching deniers by placing plants in an environment full of nutrients and water, with a 20% oxygen and 80% nitrogen atmosphere to see what happens. It could be as famous as the experiment done at Oregon State to study the impact of high pH on corals by adding sulfuric acid to a seawater fish tank.

You might want to check out the two references I recently added to my blog post echoing this.

The key trouble with the claim is that plants don't really "eat food": In the absence of sunlight (or equivalent) there is no CO2-consuming photosynthesis. In fact, under those conditions all plants do is respirate, emitting CO2, until their sugars are gone, and then they die.

Also, increased CO2 concentrations for many plants makes stomata smaller. The dynamics are complicated, as can be seen in the references, but with increased availability of CO2 it is possible that plants and the soils they grow in are at least less of a CO2 sink and could possibly tip to becoming CO2 sources.

As far as we (scientifically and collectively) know this is not the case. The claim appears to be based upon a misunderstanding of how most fossil fuels were formed.

It's best understood in the case of coal, which dates from a time when trees evolved Lignin yet there were no microbes about which could digest it. They themselves eventually evolved to be able to do so, but it took millions of years.

Meanwhile, Lignin-bearing forests died off in usual processes, and were buried, then transformed into coal beds. To quote Dr Neil deGrasse Tyson, "What possible harm could come of that?" Not only the end-Permian, but our own geologically explosive emission of greenhouse gases owes its causal origin to this evolutionary innovation. Too bad there aren't intelligent creatures about who can see burning it has serious downsides.

You might actually learn something only if you were to look ... https://en.wikipedia.org/wiki/Lignin#Biodegradationhttps://arstechnica.com/science/2016/01/why-was-most-of-the-earths-coal-made-all-at-once/https://www.e-education.psu.edu/earth104/node/584https://scholar.google.com/scholar?um=1&ie=UTF-8&lr&cites=7051516401187851516

However, these processes do not occur on human life timescales (say like six orders of magnitude longer than one hundred years).

But I'll bet you $1E6 (constant at today;s valuation) that in 1E8 years there will be brend new FF's.

See you then. /:

PS: It's really rather funny that someone would try to claim that no new FF's are possible on geological timescales (1E7-1E8 years). Or that they are too dense to even get the joke.

Quoting:In past years, there has been an increasing interest in the evolution of wood-degrading organisms. The origin of lignin degradation by fungi, associated with the appearance of the first ligninolytic peroxidases, has been estimated to have occurred during the Carboniferous period, playing a role in the decline of coal accumulation near the end of the Permo-Carboniferous (16). However, geoclimatic factors would have also significantly contributed to coal formation under ever-wet tropical conditions, and its decline could also be related to climatic shifts toward drier conditions (17, 18). Then, the expansion and diversification of genes encoding ligninolytic peroxidases occurred leading to the families existing today, as shown by genomic and evolutionary studies (16, 19, 20).

The best I can say is that there is at present an inconsistency between the Boyce-Nelson Stanford school of thought on this, as they interpret in the sedimentary record, and the evolutionary history as recorded in microbial genomes, typified by the above. (But see also Janusz, et al, 2017.) It's always good to have different opinions.

We'll see how this ends. I'd be happier if there was a confirmation of Nelson-Boyce outside of Stanford.

“Studies of proposals to use massive reforesting and afforesting to draw down CO2 from atmosphere have found limitations in the amounts of available Nitrogen as well as water. This is why, often unknown to those advocating this strategy, to really do afforestation big time would be the world's largest agricultural project. It would need massive amounts of fertilizer.”

I have seen this idea generalized into, “planting trees is not helpful”. It should be noted that trees are still very helpful in reducing the UHI effect, thereby reducing energy consumed for cooling. In winter, trees and shrubs can reduce heat loss from wind, lessening energy used for heating.

Of course some species of trees fix nitrogen; acacias, Western Red Alder, ... Some soils may be deficient in phosphorus or even potassium or sulfur. So a modest, truly modest amount of fertilizer might be required for reforestation in some localities.

But I remind you that the Sahara desert was forested around 7,000 years ago, with large lakes; all it takes is adding water to make it happen again. Read "Irrigated Afforestation of the Sahara desert and the Australian outback to ..." by Ornstein et al. The open access paper explains the general idea.

One which I opine we should start on. The Algerians and Tunisians, at least, would appreciate having the work.

I am open to doing all of this. There are limits on how much afforestation can so, estimates being something like capturing 30% of historical emissions, but that's a lot. I haven't seen cost estimates for this. Given that clear air capture and sequestration of CO2 is US$100-$300/tonne CO2, and it's crazily impossible to draw down even 50 ppm CO2 at any reasonable price accordingly, afforestation might be the cheapest thing to do.

On the other hand, there will be huge ecological and environmental consequences. And the budgeting needs to consider all the relevant effects: What's the global impact of lowering the albedo of Arabian deserts, for example. There have been proposals to go crazy planting Jatropha curcas there, except that, long term, they'll retain enough moisture to do themselves in, let alone albedo and other effects.

And, in case anyone thinks solar PV at scale and wind farms are immune from these considerations, they are not: A sufficiently large bank of wind farms off the U.S. east coast will steal enough energy to change the regional weather. Solar farms change albedo, too, although they are about the albedo of grass and trees, not parking lot pavement. I am not saying these are any reason not to do these. Indeed, I am overwhelmingly enthusiastic about large scale solar PV, especially in its decentralized form. I'm just saying doing anything big is bound to have big consequences.

This is why I am an ecomodernist and ecopragmatist: We need it all and fast. I do have serious doubts, however, about whether the discussion offered by Green New Deal and Extinction Rebellion is really up to this kind of nuanced consideration.

Also, there are a lot of engineering people who presently work in oil and gas who have lots of knowledge and experience which be handy to have when y'might want to sequester CO2 deep in rock and such, and pipe it there.

Maybe the land sink for carbon isn't a positive number, but I'm pretty sure it is a positive number as we speak. I'm also thinking peat bogs will continue to exist even if the net terrestrial carbon sink goes negative (e. g. the tropics become a net source).

Climate, decay, and the death of the coal forestshttps://www.sciencedirect.com/science/article/pii/S0960982216000646

"After death, most of the biological carbon in organisms (Corg) is returned to the atmosphere as CO2 through the respiration of decomposers and detritivores or by combustion. However, the balance between these processes is not perfect, and when productivity exceeds decomposition, carbon sequestration results. An unparalleled interval of carbon sequestration in Earth’s history occurred during the Late Carboniferous (Pennsylvanian) and Permian Periods (ca. 323–252 Ma), when arborescent vascular plants related to living club mosses (Lycophytes), ferns (Monilophytes), horsetails (Equisetophytes) and seed plants (Spermatophytes) formed extensive forests in coastal wetlands. On their death, these plants became buried in sediments, where they transformed into peat, lignite, and, finally, coal."

Mostly because it conforms to my own biases on current and ongoing coal formations. :/

A billion years of coexistence between plants and fungihttps://www.sciencedaily.com/releases/2019/02/190206123749.htm

Contemporaneous radiations of fungi and plants linked to symbiosishttps://www.nature.com/articles/s41467-018-07849-9

"The evolution of lignin-degrading fungal class II peroxidases (also called Auxiliary Activity 2 enzymes [AA2] in CAZybase) and other lignocellulolytic enzymes in Agaricomycetes enabled them to function as lignin decomposers and contributors to pedogenesis13,39. The onset of AA2s diversification was estimated between 350 and 295 Ma13 (Fig. 1). The diversification of AA2s during the early evolution of Agaricomycetes may have reduced the accumulation of peat (an organic precursor of coal) at the beginning of the Permian13. Other non-exclusive explanations for the decline in organic carbon sequestration at the end of the Permo-Carboniferous involve shifts in climate and changes in plant investment in lignin40. Current understanding of peat accumulation in the tropics suggests that peat formation is mainly determined by climate, namely precipitation exceeding evapotranspiration for at least 10 months per year41. During the Carboniferous, differential climatic conditions yielded coal of different compositions. A highly organic coal resulting mostly from chemical degradation occurred under humid conditions in which rainfall was evenly distributed, whereas coal resulting mostly from degradation by microorganisms, and with a higher mineral content, resulted from high but seasonal humidity42."

"The botanical origins of Paleozoic coal were dominated by lignin-rich, spore-bearing tracheophytes that did not form wood, and that proliferated and generated large amounts of biomass in wet and semi-aquatic habitats43. Detritivore degradation of woody plants took place before the diversification of AA2s, as indicated by the substantial contribution of Cordaites (extinct spermatophytes) to peat during specific time periods (i.e., Westphalian B-C43). The decline of lowland swamp communities started by the middle of the Late Carboniferous (Moskovian; 312–306 Ma), slightly earlier than the dated crown diversification of Agaricomycetes and probably before the diversification of AA2s13, although some of these communities held over in the Far East during the Early Permian44. Agaricomycete mushrooms, proficient in degrading lignin, are not known to degrade wood when covered by water (i.e., in anoxic conditions or where oxygen levels are low). Therefore, the decline of coal accumulation at the end of the Permo-Carboniferous may have resulted from a shift from lowland swamp communities to inland progymnosperm forests with well-oxygenated soils dominating the landscape, where Agaricomycetes with their expanded AA2s gene family could efficiently contribute to the decomposition of dead plant biomass."

"SignificanceWe analyze the molecular mechanisms that led to the rise of a powerful strategy for lignin degradation (i.e., the formation of a solvent-exposed tryptophanyl radical capable of oxidizing the bulky lignin polymer) as a convergent trait in different species of fungi (order Polyporales). We use ancestral sequence reconstruction and enzyme resurrection to obtain the ancestors of the two extant types of ligninolytic peroxidases—lignin peroxidase (LiP) and versatile peroxidase (VP)—and compare their predicted molecular structures and catalytic properties after resurrection. The results presented demonstrate convergent evolution in distant LiP and VP lineages with the exposed tryptophan residue appearing twice, as two independent events, following different molecular changes."

"Fossilized fruit bodies of a Fomes species dating back to the Tertiary (66–2.6 Ma) were reported in Idaho in 1940.[47] A fossil fruit body of Ganodermites libycus was reported from the Early Miocene (23–2.6 Ma) in the Libyan Desert. This specimen is the earliest convincing fossil evidence for the Polyporales.[48]

Molecular clock techniques have been used to estimate the age of the Polyporales, suggesting that the order evolved either during the late Jurassic, about 203–250 Ma,[14] or, in more recent study, about 114 Ma.[49]"

Above dates are a mismatch to the actual geological period of interest (Carboniferous/Permian (up through to the modern era for lower rates of coal formations from peat bogs))???

After some more reading (16) it becomes rather clear that they are misappropriating the word Carboniferous to much later geologic periods (per Wiki above) ...

"The angiosperm appearance (140–250 Mya) (41) roughly corresponds with the age of the two most recent ancestors of major clades B and D of ligninolytic peroxidases in Polyporales (∼200 Mya) that subsequently incorporated the exposed catalytic tryptophan almost at the same time (16)."

People here talking about reforestation as a sequestration solution come up against the environmental cost of large-scale planting. The same is true of essentially all decarbonation strategies. Getting rid of the massive amount of CO2 in the atmosphere and conversion to non-carbon forms of energy generation will have negative environmental impacts. Witness salmon runs in the Pacific NW and building of hydroelectric dams. Nevertheless, we move from inadvertent planetary management to some type of management where we consider the consequences.

Incidentally, a certain level of reforestation is beneficial to a forest and it sequesters some carbon, so part of the problem is scale.

If we're talking about sequestering Carbon consider the human population, which is estimated to have 287 Gt of mass. Since people are 18% Carbon, that's about 52 GtC. Annual emissions from human population (fossil fuels plus cement, basically) is 11 GtC. So the human population sequesters about 5x the annual, at least right now.

CIP, as Eli said up above this is meme engineering. As Jan said CO2 is about as low on the enthalpy scale as you can get. That is it requires a load of solar energy and protein to recycle it.

The Aussie Department of Health defines a nutrient as:

"Nutrients are compounds in foods essential to life and health, providing us with energy, the building blocks for repair and growth and substances necessary to regulate chemical processes. There are six major nutrients: Carbohydrates (CHO), Lipids (fats), Proteins, Vitamins, Minerals, Water."

No CO2. OTOH, Wikipedia has

"A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists."

Closer call, but still defensible saying that CO2 is not a nutrient.

There is a real point to this. CO2 really is the chemical endpoint of respiration, it is the garbage that cells toss off and the simile works well, not only wrt energy, but also in the sense of too much or too little being bad.

"The atmosphere is one of the Earth's major carbon reservoirs and an important component of the global carbon cycle, holding approximately 720 gigatons of carbon.[1] Atmospheric carbon plays an important role in the greenhouse effect. The most important carbon compound in this respect is the gas carbon dioxide (CO2). Although it is a small percentage of the atmosphere (approximately 0.04% on a molar basis), it plays a vital role in retaining heat in the atmosphere and thus in the greenhouse effect.[1] Other gases with effects on the climate containing carbon in the atmosphere are methane and chlorofluorocarbons (the latter is entirely anthropogenic). Emissions by humans in the past 200 years have almost doubled the amount carbon dioxide in the atmosphere."

Hmm, that last sentence appears to be a LIE of Trumpkin proportions ...

PI CO2 ~ 278 ppmvCurrent MLO CO2 ~ 412 ppmv

412/278 ~ 1.4820143884892086330935251798561 (just making sure it rounds DOWN to ONE)

So, no we are currently not even half way to a doubling (MLO is biased high wrt the global CO2 ~ 410 ppmv)

I personally don't think CO2 is garbage, I do personally think that homo sapiens are garbage or more appropriately an unsustainable organism that is taking the biggest dump from a single species that the Earth has ever seen. The G in GDP stands for Garbage,

So CO2 is a GHG that was just doing fine until you know who was added to to the mix.

"Garbage, trash, rubbish, or refuse is waste material that is discarded by humans, usually due to a perceived lack of utility. The term generally does not encompass bodily waste products, purely liquid or gaseous wastes, nor toxic waste products. Garbage is commonly sorted and classified into kinds of material suitable for specific kinds of disposal.[1]"

So in the word association meme department, remember that humans are always associated with garbage, CO2 not so much. But CO2 is a waste product of humans just like shit, piss, boogers and cum ...

So you're one of Yelpers special blessed,You demand a restaurants' very best.Well they're gonna treat you special,I'm telling you chum.Now get yourself ready for some boogers and cum.

Boogers and cum, that's called the Yelper special.Boogers and cum, say what's that on your pretzel?Your online critiques are real useful to some,Now have a good time eating boogers and cum.

Boogers and cum, someone farted on your salad?Boogers and cum, but your decor critiques are valid.You think you're special like you're number one,Well there's a whole lot of special in boogers and cum.

Boogers and cum, how 'bout some feces with your flounder?Boogers and cum, you like that queefy quarter pounder?[Yelper] What's that spice that feels tangy on my tongue?[Waiter] Oh that's the yuzu pepper, (walks away and mutters to himself) along with some boogers and cum.

[Davíd] Here you are sir.[Cartman] Thank you David that's good service.[Davíd] I will bring you food every day my friend.[Cartman] Mmm, is that a Jalapeño cream sauce?[Davíd] Yes, my father made it just for you.[Cartman] Hmm, it's tart but savory.

Boogers and cum, being a food critic's easy.Boogers and cum, oh, you feel a little queasy?Do you need a diagnosis? Well the doctors' got one.[Doctor] Your stomach seems to be filled with boogers and cum.

"Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can later be released to fuel the organisms' activities. This chemical energy is stored in carbohydrate molecules, such as sugars, which are synthesized from carbon dioxide and water – hence the name photosynthesis, from the Greek φῶς, phōs, "light", and σύνθεσις, synthesis, "putting together".[1][2][3] In most cases, oxygen is also released as a waste product. Most plants, most algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies all of the organic compounds and most of the energy necessary for life on Earth.[4]"

Hmm, oxygen? "In most cases, oxygen is also released as a waste product."

So now you know, CO2 isn't garbage but O2 and O3 are waste products. Therefore, we can say that ...

Wikipedia is a great all 'round source, and is pretty good in select areas, like statistics, but it isn't necessarily self-consistent. Given how it is written, that's hardly surprising. We have the quote above, then we have, pertaining to halobacteria or, more properly these days, haloarchaea ...

"Bacteriorhodopsin is used to absorb light, which provides energy to transport protons (H+) across the cellular membrane. The concentration gradient generated from this process can then be used to synthesize ATP. Many haloarchaea also possess related pigments, including halorhodopsin, which pumps chloride ions in the cell in response to photons, creating a voltage gradient and assisting in the production of energy from light. The process is unrelated to other forms of photosynthesis involving electron transport, however, and haloarchaea are incapable of fixing carbon from carbon dioxide."

(emphasis added)

"Most of the well-recognized phototrophs are autotrophic, also known as photoautotrophs, and can fix carbon. They can be contrasted with chemotrophs that obtain their energy by the oxidation of electron donors in their environments. Photoautotrophs are capable of synthesizing their own food from inorganic substances using light as an energy source. Green plants and photosynthetic bacteria are photoautotrophs. Photoautotrophic organisms are sometimes referred to as holophytic.[3] Such organisms derive their energy for food synthesis from light and are capable of using carbon dioxide as their principal source of carbon.

"Oxygenic photosynthetic organisms use chlorophyll for light-energy capture and oxidize water, "splitting" it into molecular oxygen. In contrast, anoxygenic photosynthetic bacteria have a substance called bacteriochlorophyll - which absorbs predominantly at non-optical wavelengths - for light-energy capture, live in aquatic environments, and will, using light, oxidize chemical substances such as hydrogen sulfide rather than water."

The above two are from Wikipedia. And then there's Oregon State University ...

"Phototrophy (or “light eating”) refers to the process by which energy from the sun is captured and converted into chemical energy, in the form of ATP. The term photosynthesis is more precisely used to describe organisms that both convert sunlight into ATP (the “light reaction”) but then also proceed to use the ATP to fix carbon dioxide into organic compounds (the Calvin cycle). These organisms are the photoautotrophs. In the microbial world, there are also photoheterotrophs, organisms that convert sunlight into ATP but utilize pre-made organic compounds available in the environment. The ATP could then be used for other purposes."

"There is a real point to this. CO2 really is the chemical endpoint of respiration, it is the garbage that cells toss off and the simile works well, not only wrt energy, but also in the sense of too much or too little being bad."

Besides, I think all this is besides the point and is legalistic casuistry: The point is that there's little energy to be exploited in a CO2 molecule, in the sense of destabilizing a structure into more primitive forms, and getting energy out of it. That's what burning is about, whether fire, or metabolic respiration of sugars, combining with Oxygen and water. That's the canonical model for eating and so the anthropomorphic use of food.

Well, y'know, if the world is going to hang on defining precisely what photosynthesis means and what it doesn't, there is going to need to be some authoritative source to consult on its meaning.

It seems to me you and CIP are trying to pick apart Eli's post by resorting to such linguistic and legal legerdemains, and when they don't work out, you accuse the opposition of introducing these in the first place.

So, what I see is you are implicitly admitting your spoutings are graffiti. Accordingly, I appreciate their color, but, in the end, they are to be disregarded and cleaned off.

"The point is that there's little energy to be exploited in a CO2 molecule, in the sense of destabilizing a structure into more primitive forms, and getting energy out of it. That's what burning is about, whether fire"

No!

We are actually burning Carbon (or C) we are not burning CO2 as CO2 is but one waste product of burning Carbon.

I would not make an argument for burning Carbon, but if I were, I say that Carbon in its natural FF's form is one of the most energy dense materials available, short of fission/fusion. That's just a coal stone hard fact.

"It seems to me you and CIP are trying to pick apart Eli's post by resorting to such linguistic and legal legerdemains, and when they don't work out, you accuse the opposition of introducing these in the first place. "

Hmm, no!

We are just regurgitating well known facts that anyone in high school would understand.

Eli is just PO'ed because of the pukes on the tooter (which means all Tower of Babel, err Twitter, users). Go figure.

And Carbon is only a deal in the presence of something else, like Oxygen. It's nothing by itself. And once it's CO2, it's worthless as an energy source. Dissociation into 1 Oxygen and CO at 1 atmosphere is just 20% at 2500C.

And as far as pendantry goes, if you don't like the movie, you can turn it off. I'm not here to entertain you, especially you. Yet you appear to remain engaged. Masochism?

But you were talking about the CO2 energy or some such nonsense, seriously, let's burn us some CO2. We'll burn it back into Carbon and Oxygen!

"And Carbon is only a deal in the presence of something else, like Oxygen. It's nothing by itself. And once it's CO2, it's worthless as an energy source. Dissociation into 1 Oxygen and CO at 1 atmosphere is just 20% at 2500C."

Where did the Carbon and Oxygen come from in the 1st place? Still puzzled by your new invention where we all turn CO2 into a fuel or energy source or some such. You are the only one trying to burn CO2 last time I checked.

"And as far as pendantry goes, if you don't like the movie, you can turn it off. I'm not here to entertain you, especially you. Yet you appear to remain engaged. Masochism?"

Well you sort of dropped of a cliff back at the citations part of the Carboniferous or some such. Don't know why.

As to my late entry into teh stoopid, I kind of like to wait to see Eli any you hang yourselves.

That CO2 is just such an EVIL molecule it should burn for eternity in HELL.

Eli referred to CO2 as "garbage", hence useless waste. Then, some, Who Knows Who, and frankly Who Cares, posited CO2 was not useless and, in particular, food for plants. This led to the unending riff on kinds of plants, what plants do, photosynthesis, Calvin Cycle, and, ultimately, critters which use light and Carbon but not CO2 to get energy. There was a big side trip on coal and Lignin.

To substantiate Eli's claim, with which I continue to fervently agree, CO2 is "garbage". And the point is the enthalpy, to which I alluded to in the dissociation evidence cited above. It's useless. But if you are a Micro Operation and you are desperate for Carbon, well, it's around, and you can finagle by proteins and sunlight to cut off the Oxygens and get it. Indeed, in the process it's a couple of steps away from the sunlight interaction. And, note, the Carbon that the Micro Operation wants isn't for burning, it's for construction.

If you can't "burn CO2" conveniently, it's waste. It's not an energy source. So, in the sense that Eli meant, and I embrace, it's "garbage".

Now, there are lots of kinds of garbage. Some are very attractive. Some are even recyclable or compostable. And, as the Composting Meister in our household, Summer or Winter, I'm pretty familiar with the Magic of the Compost. But raw CO2 isn't any of this. It's not complicated enough, so microbes just pass it by for better goodies. Methane is good, because of those sloppily attached Hydrogens. But CO2? Really?

I think that the reason for the pushback on this point, and I don't want to put anything on Eli that he doesn't agree with, is that the claim "CO2 is plant food" is just another one of a myriad number of ways that opponents of doing climate mitigation are trying to sell What We Are Doing Ain't So Bad Folks Despite What Those Commies Say.

It's a tough world to deal with, That, and an increasing foment of Wishful Environmentalism I contend with in my day-to-day.

The seesonal ups and downs of the Keeling curve are rock solid evidence that plants draw CO2 out of the atmosphere. Also proves, by extension, that C02 is food.

“In the spring, leaves return to the trees and photosynthesis increases dramatically, drawing down the CO2 in the atmosphere. This shift between the fall and winter months to the spring and summer results in the sawtooth pattern of the Keeling Curve measurement of atmospheric CO2 such that every year there is a decline in CO2 during months of terrestrial plant photosynthesis and an increase in CO2 in months without large amounts of photosynthesis and with significant decomposition.”

CO2 ain't plant food in the same sense that Oxygen isn't people food. There are no food calories in CO2 or Oxygen. However, both are essential for most life as we know it.

So, by extension, someone here is just ignorant of the facts. /:

Foodhttps://en.wikipedia.org/wiki/Food

"Food is any substance[1] consumed to provide nutritional support for an organism. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is ingested by an organism and assimilated by the organism's cells to provide energy, maintain life, or stimulate growth."

"A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin (other than liming materials) that is applied to soils or to plant tissues to supply one or more plant nutrients essential to the growth of plants. Many sources of fertilizer exist, both natural and industrially produced.[1]"

"Plants absorb carbon, hydrogen and oxygen from air. These three, in the form of water and carbon dioxide.[4] Other nutrients are absorbed from soil (exceptions include some parasitic or carnivorous plants). Counting these, there are 17 important nutrients for plants:[5]"

"Plant nutrition is the study of the chemical elements and compounds necessary for plant growth, plant metabolism and their external supply. In 1972, Emanuel Epstein defined two criteria for an element to be essential for plant growth:

(1) in its absence the plant is unable to complete a normal life cycle.(2) or that the element is part of some essential plant constituent or metabolite.

This is in accordance with Justus von Liebig's law of the minimum.[1] The essential plant nutrients include carbon, oxygen and hydrogen which are absorbed from the air, whereas other nutrients including nitrogen are typically obtained from the soil (exceptions include some parasitic or carnivorous plants).

There are seventeen most important nutrients for plants. Plants must obtain the following mineral nutrients from their growing medium:-[2]

These elements stay beneath soil as salts, so plants consume these elements as ions. The macronutrients are consumed in larger quantities; hydrogen, oxygen, nitrogen and carbon contribute to over 95% of a plants' entire biomass on a dry matter weight basis. Micronutrients are present in plant tissue in quantities measured in parts per million, ranging from 0.1[3] to 200 ppm, or less than 0.02% dry weight.[4]"

The carbon in air becomes part of a plant’s biomass, part of what the plant is made of. Proven beyond a doubt by seasonal fluctuations in the Keeling Curve. We are what we eat (true for plants as well as people), and what we eat is called food.

With minor, low-energy cost beard trims, many now derelict Confederate monuments could be repurposed as statues of Arrhenius on horseback, a cost effective move given how few Americans expect the Climate Wars to wind down before the Tercentenary

Plants get all (or most of) their energy from the sun (e. g. solar energy). Thus, the precursor for anything to happen is an energy source.

People (animals etceteras) get their energy from eating food which contains calories. Therefore, those calories are a product of something called a food chain ... people can eat plants but plants can't eat people ...

Food chainhttps://en.wikipedia.org/wiki/Food_chain

"A food chain is a linear network of links in a food web starting from producer organisms (such as grass or trees which use radiation from the Sun to make their food) and ending at apex predator species (like grizzly bears or killer whales), detritivores (like earthworms or woodlice), or decomposer species (such as fungi or bacteria). A food chain also shows how the organisms are related with each other by the food they eat. Each level of a food chain represents a different trophic level. A food chain differs from a food web, because the complex network of different animals' feeding relations are aggregated and the chain only follows a direct, linear pathway of one animal at a time. Natural interconnections between food chains make it a food web. A common metric used to the quantify food web trophic structure is food chain length. In its simplest form, the length of a chain is the number of links between a trophic consumer and the base of the web and the mean chain length of an entire web is the arithmetic average of the lengths of all chains in a food web.[1][2]"

No energy source no nothing.

The plants combine the energy source (light) with other nutrients to create sugars, those sugars are a plant's food source.

Eli, if you don't mind, please step in as necessary, as I am neither a biologist or a chemist.

The Keeling curve is just the atmospheric portion of something called the carbon cycle. All (or most) of the attributions to the Keeling Curve have been known from at least the early 1950's.

Some interesting stuff here btw Everett and Jan. On the subject of the post, Eli will take Jan's side. The meme, CO2 is garbage is not about whether the carbon atoms are necessary for building strong plants and animals, but more about the fact that the CO2 is food about as much as cinder blocks are, the later being the ashes of burnt coal compressed.

“The plants combine the energy source (light) with other nutrients to create sugars, those sugars are a plant's food source.”

And those sugars are made of hydrogen, carbon and oxygen, the latter two comimg primarily from CO2 in the atmosphere. If we narrow the definition of food to: “a plant or animal’s energy source”, as Eli, Jan and Everett have done, then sure, CO2 is not food. If we broaden the definition to include the material needed to build and maintain a plant or animal’s body mass, then CO2 most definitely IS food for plants. So it’s really just a semantic argument.

Worth noting - plants are not made of sunshine, animals are not made of calories.

The definition for food is rather simple, it provides energy in the form of calories. You can fulfill missing nutrients by taking your vitamins. /:

In the chain of events, the Sun, stars, sunshine or solar energy is first and foremost, followed by H2O (well maybe switchroo with solar or call it a tie) , then CO2 and finally nitrogen (N), phosphorus (P), potassium (K).

H, O, N, C, and P are what make up DNA.

CO2 isn't a food source simply because it contains no calories or DNA.

If one were to call CO2 a food then there are likely several hundred basic elemental combinations that should also be called food.

In addition to the most important "so called" food element of them all, solar energy which actually has the units of calories already ...

Solar constanthttps://en.wikipedia.org/wiki/Solar_constant

"Solar irradiance is measured by satellite above Earth's atmosphere,[3] and is then adjusted using the inverse square law to infer the magnitude of solar irradiance at one Astronomical Unit (AU) to evaluate the solar constant.[4] The approximate average value cited,[1] 1.3608 ± 0.0005 kW/m², which is 81.65 kJ/m² per minute, is equivalent to approximately 1.951 calories per minute per square centimeter, or 1.951 langleys per minute."

Hmm, "Solar irradiance ... is equivalent to approximately 1.951 calories per minute per square centimeter"

I would now think that this discussion is now over as far as I am concerned.

(1) Peoples common understanding of what food is. "Food is any substance[1] consumed to provide nutritional support for an organism. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals."

So carbohydrates (~4 kilocalories/gram), Fats (~9 kilocalories/gram) and proteins (~4 kilocalories/gram), vitamens and minerals are also in food which can be supplemented through pills (but should normally be included in the caloric food itself).

You might be surprised as to how many people know the 4-9-4 caloric rule mainly through dieting (or sport in my case).

So, most all people associate food with caloric intake. There can be little doubt about that basic food fact.

(2) Substitute calories for the word food, as in CO2 is plant calories, which is obviously false. So that leaves CO2 is plant food as a grossly oversimplified, misleading and incorrect statement. Based on most people's immediate 1st hand understanding of what primary food intake means.

"So is it true rising atmospheric CO2 will help plants, including food crops? Scientific American asked several experts to talk about the science behind this question.

There is a kernel of truth in this argument, experts say, based on what scientists call the CO2 fertilization effect. “CO2 is essential for photosynthesis,” says Richard Norby, a corporate research fellow in the Environmental Sciences Division and Climate Change Science Institute of Oak Ridge National Laboratory. “If you isolate a leaf [in a laboratory] and you increase the level of CO2, photosynthesis will increase. That’s well established.” But Norby notes the results scientists produce in labs are generally not what happens in the vastly more complex world outside; many other factors are involved in plant growth in untended forests, fields and other ecosystems. For example, “nitrogen is often in short enough supply that it’s the primary controller of how much biomass is produced” in an ecosystem, he says. “If nitrogen is limited, the benefit of the CO2 increase is limited…. You can’t just look at CO2, because the overall context really matters.”"

So maybe you know why Eli is so PO'ed about the oversimplified and incorrect meme. I've always known it to be an incorrect denier statement and usually stay out of arguments with deniers about CO2 is plant food, simply because it is teh stoopid thing to do.

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Eli Rabett

Eli Rabett, a not quite failed professorial techno-bunny who finally handed in the keys and retired from his wanna be research university. The students continue to be naive but great people and the administrators continue to vary day-to-day between homicidal and delusional without Eli's help. Eli notices from recent political developments that this behavior is not limited to administrators. His colleagues retain their curious inability to see the holes that they dig for themselves. Prof. Rabett is thankful that they, or at least some of them occasionally heeded his pointing out the implications of the various enthusiasms that rattle around the department and school. Ms. Rabett is thankful that Prof. Rabett occasionally heeds her pointing out that he is nuts.